This invention relates to so-called continuous motion can decorators in general and relates more particularly to interchangeable inker units for such apparatus.
Continuous motion apparatus for decorating cylindrical containers are disclosed in U.S. Pat. No. 3,223,028 issued Dec. 14, 1965 to W. E. Brigham for An Interchangeable Inking Unit For Multi-Color Presses, U.S. Pat. No. 3,859,919 issued Jan. 14, 1975 to J. P. Skrypek et al. for An Inker Unit For Continuous-Motion Printer and U.S. Pat. No. 4,741,266 issued May 3, 1988 to J. S. Stirbis et al. for Can Decorating Apparatus. In each of these three patents the decorator sections include a continuously rotating blanket wheel which transfers an image to the container being decorated. The image on the blanket wheel is derived from differently colored image segments that are imprinted by individual printing plates that are mounted on separate plate cylinders. A different colored ink is applied to each printing plate by an interchangeable inker unit.
In the apparatus of the aforesaid U.S. Pat. Nos. 3,859,919 and 3,223,028 the plate cylinder is part of the inker unit while in the aforesaid U.S. Pat. No. 4,741,266 the plate cylinder remains mounted to the main frame of the apparatus when its associated inker unit is dismounted. The advantage of having the plate cylinder separate from the inker unit is that registry between the printing cylinders does not have to be reset each time an the inker unit is changed.
In the instant invention the plate cylinder remains in the apparatus when its associated inker unit is removed. This speeds up removal and replacement of inker units. Further economy of time is achieved without sacrificing performance by having four locating depressions in the edges of vertical main frame members and utilizing quick release clamps to secure the inker unit to the main frame. These clamps engage two strong parallel rods that are parts of the inker unit. The locating rods are received by the locating depressions on the main frame.
By having the locating depressions open at the edges of frame members the support rods enter the depressions by moving radially rather than by moving axially. In the aforesaid U.S. Pat. No. 4,741,266 mounting and dismounting of the inker unit is a cumbersome procedure because it must be moved sideways through an opening in the main frame, followed by the necessity of inserting dowels into locating depressions and then threading retainer bolts to secure the inker unit to the main frame.
The type of decorating equipment in question operates at relatively high speeds so that it is preferable to utilize a liquid lubricant for the transmission elements of the inker unit. In the instant invention the transmission elements are within a housing which is essentially closed to prevent liquid lubricant from leaking out and contaminating other elements of the apparatus and/or fouling up the work area.
In the instant invention each inker unit includes three spaced parallel plates, an ink distribution section disposed between the first two plates and a transmission section disposed between the other two plates. The transmission section is disposed within an enclosure that also confines the liquid lubricant for the transmission. An input shaft of the transmission section extends sideways (horizontally) outboard of the inker unit in alignment with a drive shaft that is rotatably supported on the main frame. Mounted on the transmission shaft is a spline-type slidable collar-like gear coupling that separably connects the drive shaft with the input shaft.